You know how human lungs, if opened out and flattened, would have the same surface area as a football field? (Come to think of it, just about anything in the body reputedly unfolds to "the same surface area as a football field" --- coincidence? But I digress.)

And you know how dust tends to settle in the odd corners of a room, on book edges, in crevasses, behind refrigerators, on ceiling fan blades, and so forth?

Well, in order to protect the lungs of sensitive people (asthma sufferers, allergy victims, and the like), how about putting a huge surface area on the walls of their rooms? A fractal shape, with crannies within nooks within chinks within cracks, down to the sub-micron sizes of the most obnoxious airborne particulate matter --- that's the ultimate defense. Give it an area of millions of football fields. And make it "breathe" to pull in and trap allergens and contaminants. Give it an electrostatic charge. Make it replaceable, or renewable, or changeable. And bill the cost of it to health insurance, or the government, or somebody else impersonal and remote ....